The present invention relates to a caliper-type bow string release for archery. Such bow string releases are used by the user applying his trigger finger to apply pressure to pull the trigger, opening the jaws for loading and relaxing tension on trigger, closing the jaws around the bowstring. Such systems allow the archer to maintain one grasping finger-hand position to load and fire release. Even though many previous styles of releases can be manipulated to load on to a bowstring, it can be awkward at best. For example, earlier releases do not rotate nor allow the user to adjust the actual trigger pressure force required to fire the release.
Archery enthusiasts have never had a release available that features caliper jaws with 360-degree selectable rotation, provided by sealed ball bearings. This rotation should be in front of the trigger, which eliminates the possibility of torque being applied to the bowstring and allows for unlimited hand anchoring options that are impossible with non-rotating releases. There is also a need for the ability to easily adjust without tools the trigger pressure force required in firing the release, which is completely independent from affecting trigger travel and does not aid in the closing of the locking mechanism. These features should be combined with affordability, accuracy, ease of use, and reliability. The release must be adaptable to any style of shooting, and must be easily loaded on to a string loop or similar device. The jaws of the release should be very small in profile. This enables it to be used on all rigid center-nocking devices without having to trim arrow nocks to use them. The caliper jaws should open widely to easily load directly on to a bowstring.
Earlier U.S. patents show devices with some similarities but also several deficiencies. Examples are U.S. Pat. Nos. 5,417,197; 5,564,407; 5,582,158. The Classic Caliper has automatic latching features. The present invention has no such feature or means to accomplish that but is loaded manually by actuating the trigger. These patents disclose a push-pull, rocking mode of trigger operation to fire the release. In contrast, the present invention employs a trigger utilizing a novel ramped trigger actuator to increase the throw of the sear components with minimum input from the trigger. This decreases trigger travel necessary to fire and gives the release the quick on the edge feel the shooters crave with very low trigger pressure required to fire the release.
Earlier designs disclose a cam actuator moveable between the jaws mounted on a stem, designed to maintain the jaws in a latched open condition. The cam actuator of the present invention is designed to do the opposite, that is, to close the jaws automatically. These designs include a cam and jaw that were designed having surfaces that define trigger force adjustment. These surfaces are sear elements relying on complex cam surfaces, contact angles and positional relationships to increase or decrease sliding frictional forces seen at the trigger. This repositioning of sear elements requires precise minuscule adjustments, being careful not to make large unwanted changes in trigger pressure force. This changing of sear element positions also allows the user to set the device into an unsafe condition mistakenly while trying to adjust trigger pressure forces. These changes are made by locating a small socket set screw installed in cylindrical member, insertion of a small hex wrench loosening socket set screw while maintaining the wrench in the socket of the set screw and rotating the head and jaws to new setting, tightening the set screw to complete adjustment, and hoping you have not turned anything in a wrong direction. Additionally these earlier designs do not allow the user to preview the trigger pressures force settings selected: one must simulate loading and firing the mechanism.
The present invention has separated the trigger pressure force adjustment means from the sear components. The user may now preview their setting by simple trigger pulling action. This design does not require one to simulate loading and firing the mechanism. Since sear components are not adjusted to achieve varied trigger pressure forces, the present invention cannot be adjusted into an unsafe condition by manipulating this mechanism. The design of the present invention provides the means to adjust trigger pressure by rotation of a dial with a minimum of two fingers, and this may be done with the same hand the release is installed on (shooting hand).